Lavender: Helpful Or Placebo Effect?

Lavender and tea tree oil are among the so-called essential oils that have become popular in the United States as alternatives for medical treatment, personal hygiene and cleaning products, and aromatherapy. Various consumer products contain lavender and tea tree oil, including some soaps, lotions, shampoos, hair-styling products, cologne and laundry detergents. From its delicate purple hue to its earthy floral scent, everything about lavender seems tailored towards encouraging thoughts of serenity and peace, and as it turns out, science agrees, too.

In a recent study that was published in the journal Frontiers in Behavioural Neuroscience, researchers discovered that mice reacted particularly interestingly when taking a sniff of linalool, an alcohol component in lavender extract, which was akin basically the same as “popping a Valium,” as The New York Times put it for a human. So in other words, sniffing a key element of lavender’s unmistakable scent had an anxiety-reducing effect in mice — an effect that wasn’t observed in mice with no ability to smell at all.

While there have been a number of past studies assessing the anxiety-reducing effects of lavender, as well as many other natural alternatives, there was little to no investigation at all into the effects of the odor in itself in particular. Researchers have used lavender at the forefront of research for many years — in a previous study, one study identified that out of the six various odourant molecules examined by researchers, linalool significantly increased the pain threshold in mice. Though the effects were not tested in humans themselves, these results aren’t exactly a surprise, considering they were extremely rumoured and even considered an aspect of “old wives tales”. When you think of lavender essential oils, you think of the scent of spas and other relaxation products and peaceful locations everywhere, and you’re likely to spot a barrage of lavender room sprays and candles in the lifestyle section of any retail store. Even the ancient Greeks and Romans apparently believed the scent of lavender was soothing to untamed lions and tigers. Basically, lavender has been used for a number of things throughout history, so it’s no surprise that its positive effects have been found in this time too.

Dr. Hideki Kashiwadani, a physiologist and neuroscientist at Kagoshima University in Japan and one of the study authors, recently told The New York Times that he suspects the observed effects of linalool may be applicable to humans and other mammals, though this is yet to be tested. It’s an interesting prospect, considering that anxiety disorders are the most common mental illness in the U.S., affecting around 18 percent of the adult population, according to the Anxiety and Depression Association of America alone.

The study also exposed test mice to linalool vapor by using filter paper inside a custom-made chamber to see if the scent induced relaxation in the mice. The mice quickly exposed to linalool were more open to exploring their surroundings, suggesting they were less anxious and relaxed than the control mice who hadn’t been exposed. The mice exposed to lavender also didn’t show any signs of motor impairment, which is an effect documented in studies of mice on benzodiazepines, a drug that’s commonly used to treat anxiety. The linalool didn’t work when the mice’s ability to smell was blocked, implying that the effects were, in fact, caused by scent itself, and that in order to work, linalool triggered odor-sensitive neurons in the nose that send signals to certain areas of the brain.

So what does all this mean? Well, the study found that the olfactory system was key for inducing anxiety-reducing effects. The findings help lay a foundation for further exploration of the potential clinical uses of linalool odor (or other lavender-based products) in anxiety treatments, and the medical field in general. Whether you’re taming a tiger, making a mouse more comfortable in it’s surroundings or decreasing anxiety in humans, it seems lavender is something that’ll stick around for a long time.